Diet, Health, Fitness, Lifestyle & Wellness

Tag Archives: pollution

The great recession

What do economics have to do with health? At most universities they’re not even in the same building! But it turns out that a dip in the economy can lead to a rise in our weight according to a study done by John Hopkins. Researchers found that from 2008 to 2012—the period known as the great recession—weight gain was strongly correlated with the rise in unemployment, increasing the risk of obesity by 21 percent. This makes sense as one of the first things to go when our budgets get tight are luxuries like health food and gym memberships, not to mention the loss of health insurance that often accompanies a job loss. However, it may help to remember that there are many low-cost or free ways to protect your health—and an investment in you is the best one you can make.

How high you are

No we’re not talking about the wave of pot legalization sweeping the country (although that probably would affect your weight too) but rather how high up you live. There’s a reason that Colorado is the both the slimmest and the steepest state in the nation. The altitude at which you live is strongly correlated with your weight, with each gain in altitude corresponding with a drop in weight, according to a study done by the U.S. Air Force. But don’t sell your beach-front property and head for the hills just yet—the effect can be balanced out by other factors known to prevent against obesity where you live, like outdoor greenery, strong social ties, and opportunities to go outside. Case in point: Hawaii is the third thinnest state in America, and it’s the definition of sea level.

It’s a generation thing

Ever wondered why your grandma never exercised a day in her life and yet wore a tiny wedding dress that you could never hope to fit into even though you run marathons? Some of it may be due to the difference in generations you were both born into. Bad news for young ‘uns: Millennials, Gen Y, and Gen X all need to eat less and exercise more to stave off obesity than their forefathers did, according to a study from York University. And it’s not just the fact that we have Netflix and take out at our fingertips. Rather, the researchers found that the average metabolism of both men and women has slowed, even after controlling for factors like disease, diet, and fitness. Why? We have no solid answers yet but in the meantime, if you’re under 40 at least you can take comfort that you’re not alone in your struggle.

That cursed smog

The effects of environmental pollutants go far beyond wheezing and sneezing. Rats exposed to highly polluted air were not only much more likely to become obese, according to a study done by Duke University, but also had a greater risk of heart disease, diabetes, and metabolic syndrome. And it’s not just limited to rodents. People who live close to roadways with a high level of air pollution are also more likely to gain weight, says a study from the University of Southern California. Unfortunately air pollution is likely not under your direct control but we can all work together to lobby for and implement clean-air policies where we live, making for both a healthier physical and celestial body.

Your thermostat

Our delightfully warm and cozy homes and offices might be partly responsible for our less-delightful expanding waistlines, say researchers in a study published in the journal Cell. The scientists found that regular exposure to mildly cold weather—as would have been normal in the days before programmable thermostats—helps the human body regulate a healthy weight. The chilly air seems to increase metabolism by making the body work harder to cope with the changing conditions. Some proponents of “cold therapy” take daily ice baths or “shiver walks” but you don’t have to be that extreme to see results, say the researchers. Just lowering your thermostat by a few degrees or turning the shower briefly to cold can help.

How many antibiotics you’ve taken

Antibiotics are one of the biggest miracles of modern medicine, no doubt about it. But those infection-fighting drugs may have unintended consequences. The more antibiotics a person takes during their lifetime, particularly during early childhood, the greater their risk of becoming obese, according to an NYU study. Researchers speculate that it has to do with killing healthy gut bacteria, decimating your microbiome along with the bad bugs, as good bacteria has been shown to help prevent weight gain. But if you were the kid with chronic ear infections, don’t fret, you can rebuild your good gut bacteria by taking a probiotic and eating plenty of fermented foods such as yogurt, kefir, sauerkraut, and kimchi.

Fido and Fifi

Owning a pet, particularly a dog, slashes the human companion’s risk of obesity, says the American Heart Association. Why? Dogs need to be walked daily and are often quite persistent, encouraging their owners to walk as well. But it’s not just the extra exercise, especially since 40 percent of dog owners confess to not walking their dog on a regular basis. The researchers add that petting an animal greatly reduces stress and depression, two other known risk factors for weight gain. So if you do have a dog, make sure to walk them daily, and in the meantime soak up all the snuggles, wet kisses, and purrs you can.

The number on your paycheck

Income is one of the biggest factors correlated with obesity, with poor Americans being three times more likely to be obese than richer ones, according to a study published in Nutrition Reviews. Low-income people are less likely to have access to supermarkets with fresh foods (often living in “food deserts”), less likely to have health insurance, and less likely to live in neighborhoods where exercise outdoors is encouraged or even safe. Fortunately this is one area we can all help improve by working to better conditions in our own neighborhoods or helping out others nearby.

Pesticides

Pesticides may help us grow stronger and more plentiful crops but many of the chemicals used in popular formulations are known “endocrine disruptors”: They interfere with your body’s metabolic systems. Pesticides hijack our metabolism by mimicking, blocking, or otherwise interfering with the body’s natural hormones, according to a report issued by The Endocrine Society. Regular exposure to pesticides through food was correlated with an increase risk of both obesity and diabetes. Buying all organic may be one solution but for many people that doesn’t fit in the budget. If money’s tight you can also decrease your pesticide load by avoiding, or only buying organic of, the “dirty dozen“, the most contaminated produce. Or you can always try growing some of your own fruits and vegetables. (Bonus: Gardening is great exercise!)

How many trees you can count from your window

Close proximity to parks, trails, and other types of green spaces is linked with lower body weight, according to research done by the American Diabetes Association. Being able to see, and more importantly walk to, greenery encouraged people to exercise more and made it feel, well, less like exercise. Parks make physical exertion feel like fun but even if you’re not using them to exercise, simply being in the presence of nature has been shown to reduce stress, lower weight and improve your health overall. The vast majority of Americans already live within walking distance of some type of park so get out there and explore your neighborhood.

All that stuff on the food label you don’t recognize

You already know that processed foods do no favors for your waistline but it turns out it’s not just the empty calories and trans fats doing the damage. Some of the most popular food additives are linked with weight gain and obesity, according to a study done by Georgia State University. Emulsifiers, which are added to most processed foods for texture and to extend shelf life, are one of the worst offenders as they interfere with good gut bacteria. But some artificial flavorings, artificial sweeteners, preservatives, and even the food packaging have also been linked in research to obesity.

Researchers examined 11 different brands of water purchased in 9 countries

The bottled water industry is estimated to be worth nearly $200 billion a year, surpassing sugary sodas as the most popular beverage in many countries. But its perceived image of cleanliness and purity is being challenged by a global investigation that found the water tested is often contaminated with tiny particles of plastic.

“Our love affair with making single-use disposable plastics out of a material that lasts for literally centuries — that’s a disconnect, and I think we need to rethink our relationship with that,” says Prof. Sherri Mason, a microplastics researcher who carried out the laboratory work at the State University of New York (SUNY).

The research was conducted on behalf of Orb Media, a U.S-based non-profit journalism organization with which CBC News has partnered.

Mason’s team tested 259 bottles of water purchased in nine countries (none were bought in Canada). Though many brands are sold internationally, the water source, manufacturing and bottling process for the same brand can differ by country.

The 11 brands tested include the world’s dominant players — Nestle Pure Life, Aquafina, Dasani, Evian, San Pellegrino and Gerolsteiner — as well as major national brands across Asia, Africa, Europe and the Americas.

Researchers found 93 per cent of all bottles tested contained some sort of microplastic, including polypropylene, polystyrene, nylon and polyethylene terephthalate (PET).

10.4 particles/litre on average

Microplastics are the result of the breakdown of all the plastic waste that makes its way into landfills and oceans. They are also manufactured intentionally, as microbeads used in skin care products. Microbeads are now being phased out in Canada, after significant numbers began to appear in the Great Lakes and the tiny particles were found filling the stomachs of fish.

Anything smaller than five millimetres in size (5,000 microns) is considered microplastic.

Orb found on average there were 10.4 particles of plastic per litre that were 100 microns (0.10 mm) or bigger. This is double the level of microplastics in the tap water tested from more than a dozen countries across five continents, examined in a 2017 study by Orb that looked at similar-sized plastics.

Other, smaller particles were also discovered — 314 of them per litre, on average — which some of the experts consulted about the Orb study believe are plastics but cannot definitively identify.

The amount of particles varied from bottle to bottle: while some contained one, others contained thousands.

The purpose of the study was to establish the presence of the plastics in bottled water.

It’s unclear what the effect of microplastics is on human health, and no previous work has established a maximum safe level of consumption. There are no rules or standards for allowable limits of microplastics in bottled water in Canada, the United States and Europe. Rules and standards for other countries from the study are not known.

Two brands — Nestle and Gerolsteiner — confirmed their own testing showed their water contained microplastics, albeit at much lower levels than what Orb Media is reporting.

Emerging science

Plastics are present nearly everywhere and can take hundreds of years to degrade, if at all. Many types only continue to break down into smaller and smaller particles, until they are not visible to the naked eye.

Plastics have also been known to act like a sponge, and can absorb and release chemicals that could be harmful if consumed by mammals and fish.

“It’s not straightforward,” said Prof. Max Liboiron of Memorial University in St John’s.
“If you’ve ever had chili or spaghetti and you put it in Tupperware, and you can’t scrub the orange colour out, that’s a manifestation of how plastics absorb oily chemicals,” says Liboiron, director of the Civic Laboratory for Environmental Action Research (CLEAR), which monitors plastic pollution.

The European Food Safety Authority suggests most microplastics will be excreted by the body. But the United Nations Food and Agriculture Organization has raised concerns about the possibility some particles could be small enough to pass into the bloodstream and organs.

It’s not clear how the plastic is getting into the bottled water — whether it’s the water source itself or the air or the manufacturing and bottling process.

“Even the simple act of opening the cap could cause plastic to be chipping off the cap,” Mason said.

The science behind the test

The water tested was purchased in the U.S., Kenya, China, Brazil, India, Indonesia, Lebanon, Mexico and Thailand, and represented a range of brands across several continents. It was shipped to the specialized lab at SUNY in Fredonia, N.Y.

Scientists used Nile Red fluorescent tagging, an emerging method for the rapid identification of microplastics, as the dye binds to plastic. Scientists put the dyed water through a filter and then viewed samples under a microscope.

Mason’s team was able to identify specific plastics over 100 microns (0.10 mm) in size but not smaller particles. According to experts contacted by CBC News, there is a chance the Nile Red dye is adhering to another unknown substance other than plastic.

Mason leaves open that possibility but leans strongly to the smaller particles being plastic.

The developer of the Nile Red method agrees.

Fluorescing particles that were too small to be analyzed should be called “probable microplastic,” said Andrew Mayes, senior lecturer in chemistry at the University of East Anglia in the U.K.

Orb consulted several toxicologists and microplastics experts throughout the entire process who also reviewed the findings.

“This is pretty substantial,” Mayes said. “I’ve looked in some detail at the finer points of the way the work was done, and I’m satisfied that it has been applied carefully and appropriately, in a way that I would have done it in my lab.”

CBC News also asked multiple experts to review Orb’s study; while similar questions came up with the Nile Red dye, they were convinced there was some level of microplastics in the water and further research was warranted.

Big brands respond

Nestle said in a response that it had tested six bottles of water from two of its brands — Nestle Pure Life and San Pellegrino — and found between two and 12 microplastics per litre, much lower than what Orb found in its study. The company suggested that Nile Red dye is known to “generate false positives.”

Gerolsteiner also said its tests showed a “significantly lower quantity of microplastics per litre” in its products.

“We still cannot understand how the study reached the conclusions it did,” the company said. “The research results do not correspond to the internal analyses that we conduct on a regular basis,” the company said in a response.

Danone, the company behind Evian and Indonesian brand Aqua, told Orb it is “not in a position to comment as the testing methodology used is unclear. There is still limited data on the topic, and conclusions differ dramatically from one study to another.”

Brazilian brand Minalba told Orb that it abides by all quality and security standards required by Brazilian legislation.

The American Beverage Association, which represents many of the biggest brands across North America, including Nestle, Evian, Dasani and Aquafina, told Orb that “the science on microplastics and microfibres is nascent and an emerging field…. We stand by the safety of our bottled water products and we are interested in contributing to serious scientific research that will … help us all understand the scope, impact and appropriate next steps.”

Brands Biserli and Wahaha did not respond to Orb’s request for comment.

Plastics, plastics everywhere

Within three decades, there will be more plastics in the oceans than fish. They are having a profound effect on the environment. In the oceans, vast quantities float on the surface, trapping sea life and blocking the sun’s rays from entering the waters.

Mason points out people can choose to not buy water in a plastic bottle, and to carry a refillable bottle instead. But for other products, there is no choice. The majority of products on grocery and retail store shelves are contained in plastic.

“It’s portable, it’s lightweight, it’s convenient, it’s cheap — that just makes it easy,” Mason says. “It’s so difficult to get people to care about things they can’t see.”

Given the health dangers posed by a warming climate, study authors focused on a key question: How well is the world responding?

In recent years, the ranks of climate change migrants have grown. Twenty-five homes have been abandoned on Louisiana’s Isle de Jean Charles, which is being overtaken by the Gulf of Mexico.

Climate change significantly imperils public health globally, according to a new report that chronicles the many hazards and symptoms already being seen. The authors describe its manifestations as “unequivocal and potentially irreversible.”

Heat waves are striking more people, disease-carrying mosquitoes are spreading and weather disasters are becoming more common, the authors note in the report published Monday by the British medical journal the Lancet. Climate change is a “threat multiplier,” they write, and its blows hit hardest in the most vulnerable communities, where people are suffering from poverty, water scarcity, inadequate housing or other crises.

“We’ve been quite shocked and surprised by some of the results,” said Nick Watts, a fellow at University College London’s Institute for Global Health and executive director of the Lancet Countdown, a project aimed at examining the links between climate change and public health.

The effort involved 63 researchers from two dozen institutions worldwide, including climate scientists as well as ecologists, geographers, economists, engineers, mathematicians, political scientists and experts who study food, transportation and energy.

The Countdown, as its ticking-clock title suggests, outlines the way humans are adapting — or not — to a rapidly evolving climate. It was announced last year during the United Nations Climate Change Conference in Morocco. The project, a synthesis of scientific literature and media reports, tracks 40 indicators of human health, including migration, nutrition and air pollution.

Given the profound health dangers posed by a warming climate, the study’s authors focused on a key question: How well is the world responding?

“The answer is, most of our indicators are headed in the wrong direction,” Watts said. “Broadly, the world has not responded to climate change, and that lack of response has put lives at risk . . . The impacts we’re experiencing today are already pretty bad. The things we’re talking about in the future are potentially catastrophic.”

Hotter global temperatures are exacting a human toll. Although the increase since 2000 may seem slight — about 0.75 degrees Fahrenheit — the planet is not a uniform oven. Local spikes can be dramatic and dangerous. Heat waves, defined as extreme temperatures that persist for at least three days, are on the rise.

Between 2000 and 2016, the number of people exposed to heat waves climbed by 125 million vulnerable adults, according to the report. During 2015, the worst year on record, 175 million people suffered through sweltering temperatures.

Watts also cited the rising number of deaths from floods, storms and other weather disasters. Each year between 2007 and 2016, the world saw an average of 300 weather disasters — a 46-per-cent increase from the decade between 1990 and 1999. In the 25 years since 1990, these disasters claimed more than 500,000 lives.

The number of potentially infectious bites from the Aedes aegypti mosquito, which spreads viruses such as dengue fever and Zika, is up 9 per cent over 1950s levels.

And in recent years, the ranks of climate change migrants have grown. Just in the United States, more than 3,500 Alaskans have fled coastal erosion and permafrost melts. Twenty-five homes have been abandoned on Louisiana’s Isle de Jean Charles, which is being overtaken by the Gulf of Mexico. In 2016, its former residents became the first to receive federal funds for a climate change retreat.

“If governments and the global health community do not learn from the past experiences of HIV/AIDS and the recent outbreaks of Ebola and Zika viruses,” the authors warn in the paper, “another slow response will result in an irreversible and unacceptable cost to human health.”

But Monday’s report also finds “glimmers of hope,” Watts said. For example, many countries are moving away from coal-fired power plants, which are a source both of carbon emissions that fuel global warming and pollution that can cause immediate health problems in nearby communities.

After U.S. President Donald Trump’s announcement in June that the United States would pull out of the Paris climate accord, the global response to climate change has been heartening, the authors write, “affirming clear political will and ambition to reach the treaty’s targets.” Nicaragua, previously a holdout because it said the treaty was not stringent enough, is set to join the Paris agreement, leaving only Syria and the United States opposed.

Watts and his co-authors note the ways people are trying to cope with the effects of climate change — spending less time outdoors, for example — even as they warn that the world cannot rely on adaptation alone.

“If anybody says we can adapt our way out of this, the answer is, of course you can’t,” he said. “Some of the changes we’re talking about are so enormous, you can’t adapt your way out.

Pollution was responsible for nine million deaths around the world in 2015, and although many were in industrializing countries, Canada has not been immune to the harm, a newly released study says.

It’s a toll that’s three times higher than deaths from AIDS, tuberculosis and malaria combined and 15 times higher than from wars and other violence, according to the Lancet Commission on Pollution and Health, whose findings were released on Thursday in the medical journal The Lancet.

The commission is a pollution research effort uniting Lancet, the Global Alliance on Health and Pollution and the Icahn School of Medicine in New York.

Tensions rising as Chinese no longer willing to hold their breath on pollution problems

The deaths from illnesses and diseases linked to the pollutants are considered premature, the report says, because they would otherwise not have occurred without exposure to the various forms of pollution.

“Nearly 92 per cent of pollution-related deaths occur in low-income and middle-income countries and, in countries at every income level, disease caused by pollution is most prevalent among minorities and the marginalized,” the study said.

India, many countries in Africa and some South American countries have been hit particularly hard, said Bruce Lanphear, a health-sciences professor at Simon Fraser University, one of 40 commissioners involved in the two-year research project.

“This is the first global estimate of the total burden of disease due to pollution, and we’re not just talking about air pollution,” Mr. Lanphear said.

The researchers refer to air pollution from such sources as fossil-fuel combustion and the burning of biomass. They also refer to water and soil pollution and toxic-chemical pollution at work sites.

“It’s very likely, if not certain, that we have underestimated the impact of pollution because in some countries, it’s very hard to get data. In other cases, the evidence on the increase in death, disability and disease is still coming out,” Mr. Lanphear said.

Mr. Lanphear said that while air pollution and other pollutants are more problematic in industrializing countries, they are still a sizable burden in a country such as Canada.

“We regulate toxic chemicals in Canada as though there are safe levels or thresholds, but what we’re finding is that is not true for some of the most well-studied toxic chemicals,” he said, citing asbestos, fine airborne particulates and benzene.

He said Canada is “absolutely not” in the clear on the issue. For example, he said heart disease can result from air pollution, including second-hand tobacco smoke, and malignant mesotheiloma can result from past exposures to asbestos.

Mr. Lanphear said pending plans to reform the Canadian Environmental Protection Act, first enacted in 1988 and revised in 1999, might provide the opportunity to bolster measures for dealing with pollution. The act governs toxic substances, vehicle and engine emissions, among other factors affecting the environment.

The research also says pollution-related diseases are annually responsible for $4.6-trillion (U.S.) in “welfare losses,” defined as economic costs beyond disease and treatment such as loss of productivity. Pollution, says the research, is also responsible for 1.7 per cent of annual health-care spending in high-income countries.

Over all, the Lancet study calls for measures to quantify and then curb pollution, which it describes as an “unintended consequence of unhealthy and unsustainable development.”

“If we want to substantially reduce the global environmental burden of disease, we need to act further upstream and address the drivers and sources of pollution to ensure that development policies and investments are healthy and sustainable by design.”

Pollution, say the authors, can “no longer be viewed as an isolated environmental issue, but is a transcendent problem that affects the health and well-being of entire societies.”

“This is an interesting source of pollution because emissions from dryer vents are essentially unregulated,” said lead author Dr. Anne Steinemann, professor of civil and environmental engineering and of public affairs at the University of Washington, said in a written statement. “If they’re coming out of a smokestack or tail pipe, they’re regulated, but if they’re coming out of a dryer vent, they’re not.”

Previous studies have looked at what chemicals are released by laundry products, since manufacturers don’t have to disclose ingredients used in fragrances or laundry products.

Needless to say, these researchers weren’t thrilled with what they found.

For the study – published in the August issue of Air Quality, Atmosphere and Health – researchers enlisted two homeowners to volunteer their washers and dryers, which the team scrubbed clean beforehand. The researchers ran a regular laundry cycle for three scenarios in each home: once without any detergent, once with a scented liquid laundry detergent, and the last with both scented detergent and a leading brand of scented dryer sheets.

Their analysis found more than 25 “volatile” air pollutants – including the carcinogens acetaldehyde and benzene.

Benzene causes leukemia and other blood cancers, according to the American Cancer Society. Acetaldehyde has been shown to cause nasal and throat cancer in animal studies.

Steinemann thinks agencies focus too much on limiting other pollution sources when they should look closer to home.

“We focus a lot of attention on how to reduce emissions of pollutants from automobiles,” she said. “And here’s one source of pollutants that could be reduced.”

The American Cleaning Institute, however, Steinemann’s study, calling the findings “shoddy science” that didn’t take into account many factors like washing machine brands, different load cycles, and non-scented products.

“Consumers should not be swayed by the sensationalist headlines that may come across the Internet related to this so-called research,” the Institute emailed CBS News.

Eighty percent of cancers are due to factors that have been identified and can potentially be controlled, according to the National Cancer Institute. And not only can we potentially prevent most cancers, we can also improve the survival rates of people who have cancer. Cancers of the breast, prostate, and colon have received more research attention than other forms of the disease, but, as we will see, certain principles apply to many forms of cancer.

Cancer starts when one cell begins to multiply out of control. It begins to expand into a lump that can invade healthy tissues and spread to other parts of the body. But there is a lot we can do about it. Thirty percent of cancers are caused by tobacco. Lung cancer is the most obvious example, but by no means the only one. Cancers of the mouth, throat, kidney, and bladder are also caused by tobacco.

Dietary factors also play a significant role in cancer risk. At least one-third of annual cancer deaths in the United States are due to dietary factors.1 A review on diet and cancer estimates that up to 80 percent of cancers of the large bowel, breast, and prostate are due to dietary factors. 1

In 2008, excess body weight was responsible for over 124,000 new cancer diagnoses in Europe. These results were presented at a major European cancer conference in 2009 and showed endometrial (uterine) cancer, postmenopausal breast cancer, and colorectal cancer were the most common weight-related cancers. These three cancer types accounted for 65 percent of all cancers due to excess body weight. The effects of obesity also appear to increase mortality from several other types of cancer including gallbladder, pancreas, kidney, cervix, and ovary, as well as non-Hodgkin’s lymphoma in women with the highest BMIs compared to those with a healthy BMI.2 Previous studies including the Adventist Health Study-2 show that following a vegan diet results in the lowest BMI of any group (lacto-ovo-vegetarian, pesco-vegetarian, semivegetarian, nonvegetarian), making them less susceptible to obesity-related cancers. 3

The link between diet and cancer is not new. In January 1892, Scientific American printed the observation that “cancer is most frequent among those branches of the human race where carnivorous habits prevail.” Numerous research studies have shown that cancer is much more common in populations consuming diets rich in fatty foods, particularly meat, and much less common in countries eating diets rich in grains, vegetables, and fruits. One reason is that foods affect the action of hormones in the body. They also affect the strength of the immune system and other factors. While fruits and vegetables contain a variety of vitamins, minerals, antioxidants, and phytochemicals to protect the body, by contrast, recent research shows that animal products contain potentially carcinogenic compounds which may contribute to increased cancer risk. 5

In addition to tobacco use and diet, other factors, including physical activity, reproductive and sexual behavior, 4 bacterial and viral infections, and exposure to radiation and chemicals, may also contribute to the risk of certain forms of cancer. 4,6

Dementia affects tens of millions of people worldwide. Common risk factors include age, family history, and genetics. But new research points to an additional factor that might affect the chances of developing dementia: living near a major, busy road.

Living next to a major roadway may increase the chances of developing dementia.

Dementia describes a wide range of brain illnesses that progressively lead to the loss of cognitive functioning. It affects reasoning, memory, behavior, and the ability to perform daily tasks.

The World Health Organization (WHO) report that approximately 47.5 million adults are currently affected by dementia worldwide.

The most common risk factors are age, family history, and hereditary background. While these are outside of one’s control, there are additional risk factors that could be controlled. These include avoiding head trauma and other conditions that damage the heart and blood vessels, such as hypertension, heart disease, diabetes, and high cholesterol.

Emerging research highlights a new element that might influence the chances of developing dementia – living close to major, busy roads, such as highways or motorways.

Examining the link between major road proximity and dementia

Researchers from Public Health Ontario, Canada – in collaboration with several Canadian universities and Health Canada – have set out to examine the link between residential proximity to major roads and the incidence of dementia in Ontario.

Their results were published in The Lancet.

More specifically, the team, led by Dr. Hong Chen, looked at three major neurodegenerative diseases: dementia, Parkinson’s disease, and multiple sclerosis (MS).

The scientists were motivated by existing research that has previously linked living near a major road to negative effects on the residents’ cognition. Some studies have suggested that exposure to traffic and its side effects, such as noise and pollution, might contribute to neurodegenerative pathology.

In this new study, the Canadian researchers followed a total of 6.6 million Ontarians aged between 20 and 85 for over a decade, between 2001 and 2012.

The team used postcodes to determine the proximity of the residents to major roadways. The researchers also used the participants’ medical records to see if they developed dementia, Parkinson’s, or MS over the years.

Almost everyone (95 percent of the participants) in the study lived within 1 kilometer of a major road. Over the 10-year period, the researchers identified 243,611 cases of dementia, 31,577 cases of Parkinson’s disease, and 9,247 cases of MS.

One in 10 dementia cases attributable to traffic exposure

Researchers found no association between living next to a major roadway and developing Parkinson’s disease or MS. However, dementia was found to be more common among people who lived closer to busy roads.

The study revealed that up to 1 in 10 cases of dementia among residents living within 50 meters of a major road could be attributed to traffic exposure. Additionally, the closer people lived to the busy roads, the higher their risk of developing dementia was.

Between 7 and 11 percent of the dementia cases identified were attributable to major road proximity.

The risk decreased the farther away people lived from the main road. The results suggest that the risk of dementia was 7 percent higher for those living within 50 meters of a major roadway. This dropped to 4 percent for those living within 50-100 meters, 2 percent for those at 101-200 meters, and there was no increase in risk for those living more than 200 meters away.

Dr. Chen and team also found a link between long-term exposure to two common pollutants – nitrogen dioxide and fine particulate matter – and the incidence of dementia.

Although the link between dementia and road proximity weakened when researchers adjusted for these two pollutants, this association did not fully account for the entire near-road effect. This suggests that other pollutants, or even factors such as noise, could play a role.

Findings ‘open up crucial global health concern’

Strengths of this study include its large scale, as well as the access that researchers had to detailed medical and residential information over a period of 10 years. The study also adjusted for factors including socioeconomic status, education, body mass index, and smoking.

Limitations of the study include its observational nature, which means that it could not establish causality. Furthermore, the pollution exposure was estimated based on the postcode, so the study could not consider the pollution that each individual may have been exposed to.

The authors highlight the significance of their study in light of the growing prevalence of dementia, and the limited information researchers and healthcare professionals have on its causes and prevention.

“Our study suggests that busy roads could be a source of environmental stressors that could give rise to the onset of dementia. Increasing population growth and urbanization have placed many people close to heavy traffic, and with widespread exposure to traffic and growing rates of dementia, even a modest effect from near-road exposure could pose a large public health burden. More research to understand this link is needed, particularly into the effects of different aspects of traffic, such as air pollutants and noise.” Dr. Hong Chen

Dr. Lilian Calderón-Garcidueñas from the University of Montana – who did not collaborate with researchers on this study but who has conducted extensive research on the link between air pollutants and brain pathology – also weighed in on the findings.

The mounting evidence linking dementia and road traffic, she says, “opens up a crucial global health concern for millions of people […] The health repercussions of living close to heavy traffic vary considerably among exposed populations, given that traffic includes exposures to complex mixtures of environmental insults […] We must implement preventive measures now, rather than take reactive actions decades from now.”